The aging American Population is exerting increasing demands on an already overburdened and costly health care system. Home health care is an alternative that has considerable promise alleviating burdens and costs. Medical devices utilizing advanced technology will be an increasing factor in home health care. An important issue concerns the ability of older people to operate these devices safely and effectively. This research proposal addresses this issue by (a) characterizing the cognitive, sensory, and physical capabilities and limitations of the elderly that can impact upon the operation of home medical devices and (b) applying cognitive engineering and human factors analyses to selected home medical devices and their instructional materials. The Phase I research will identify and evaluate device design and instructional factors that critically affect device use by the elderly. This research will provide valuable information for (a) improving device design and instructional material guidelines for elderly users, (b) recommending technological innovations such as on-line help systems and voice technology, and (c) expanding the scope of in vitro self-testing, (d) suggesting federal guidelines for requisite device features, and (e) tailoring the user-device interface to elderly users.